Bituminous composition



Patented July 29, 1930 UNITED stares rarENr orru :s

'rHoMAs FRASER KING, or EAST GREENWIGH, LoNnoN, ENGLAND BITUMINOUS (l-OMPOSI'JIION No Drawing. Application filed August 30, 1929 Serial No. 389,605, and in Great Britain August 3, 1928.

This invention relates to bituminous compositions for use as b nders or cements whlch are'particularly suitable in connection with the formation of roads. subjected to heavy traflic, for spraying such surfaces and for use in the manufacture of-blocks suitable for street paving, and other purposes.

The invention has for its object to pro- ,vide'an improved binder, or cement. A further object is to enable an aggregate of earthy material of anykind not ordinarily employable, such as mud, sand,:.clay, disintegrated stone, as ordinarily encountered during excavations, to .beutilized to form blocks or slabs. or to form aroad or like-structure which is extremely hard, strong and resilient yet such that good resultscan be obtained by the use of a low proportion (sayiabout,

5 to 8 per cent.) of bituminous material in the-finished product. r

A further ob ect 1s to produce a bituminous composition suitable for hot spraying roads and the like. The invention consists, briefly in a bituminous compound for use when heated as a spraying or" binding material or cement (for admixture with an aggregate) comprlsing chalk and/or powdered limestone or equivalent calcium. compound, artificially-pro.

,30 duced bituminous material e. g. coal tar or its equivalent in natural bituminous material ,or mixtures thereof includingor associated with hard. pitch together with a small proportion of alum. p J r u The invention also consists in a bituminous compound as set forth above wherein the proportion of chalk (orequivale'ntcalcium. compound) to bitumen is about two parts to one by weight and the amount of 'io'alumis about l per cent. by weight of the mixture. I I,

- The invention also consists in a spraying or binding material as set forth above where in theingredients are associated in the following approximate proportions binding material are approximately i 7 Per cent Chalk 67 Alum 1 PltCl1 Coal tar or bituminous equivalent in natural bituminous material 16 The invention also consists in a hot spray ing bituminous material comprising approximately 7 lbs. of gas tar, 1 lb. of hard pitch, 16 lbs.'of powdered chalk and 1 ounceof powdered alum. i The invention also consists in a bituminous composition for use, when heated, as a binder or cement, comprising chalk, alum, hard pitch and coal tar or its equivalent.

The invention also consists in a bituminous compositlon as set forth above, wherein the-ingredients are heated together and the resultant mass'is used for casting blocks or slabs or for admixture with an aggregate to form. a road-making or similar material. 7 The invention alsoconsists in a compositionas set forth above, wherein the ingredients are heated together with theaddition of'naphtha or creosote or otherbitumi- ,7

nous oils The lnvention also conslsts in a road-making or like material including an aggregate and a binder as set forth above, i'nfwhich the proportion of bituminous materialls small, e.'g. of the orderof 5 per cent.

- i The invention also consists in a'road-making or like material embodying a binder constituted as set forth aboveassoci'ated with an aggregate of excavation material comprisin mainly soil with which may be mixed wet or dry clay, with or without broken gravel.

The invention also consists in a road-making or like material embodying a binder constituted as set forth above associated with an aggregate comprising mainly river mud, such as Thames mud and/or wet or dry clay.

The invention also consists in binders, sprays, roads, blocks or like materials constructed substantially as hereinafter described.

In carrying the invention into effect in one form by way of example, toproduce a hot bituminous binder I mix chalk, potash alum, coal tar and commercial hard pitch in the rel.- ative proportions by weight of about 65, 1, 17 and 17 per cent. It is preferred that the chalk particles should be of coarse formation rather than of the formation of the particles found in whiting. According to another ex ample powdered limestone is substituted for some or all of the chalk. The coal tar employed is preferably low in free carbon content and the pitch should not have been produced by distilling at such a high temperature as to present a pitted appearance when set. The mixing is conducted at a tempera,

ture which is not so high asto cause decomposition of the bituminous material and the binder produced is ready for use in a variety of ways. For example, the binder may be admixed with an aggregate constituted by an old road formation comprising for example dirty and disintegrated stone, sand, loam or even clay, the whole being heated in an ordinarv asphalt cooker, a small quantity of asphaltic oil flux being added as a thinner when required. The resulting matrix when sufficiently heated may be laid hot as a foundation or undercoat, the proportion of binder to aggregate depending upon the nature of the foundation required, it being understood that the pitch contributes hardness while the bituminous content imparts resilience and tenacity.

A similar mixture may be employed for the surface layer, the coarser lumps, however, being removed from the aggregate; also the bituminous content preferably being somewhat increased as compared with that employed in the undercoat. J It is preferred to effect the mixing of the ingredients of the binder in large quantities say 5 hundredweight or more at a time. When, however, it is necessary to mix in small quantities the proportion of chalk may be reduced greatly to facilitate mixing.

A road material laid as described above is extremely hard and dense and yet possesses resilience and if applied to a thickness comparable to that adopted in the case of cement concrete possesses marked superiority as regards utility to'withstand crushing stresses, resilience and waterproofness while having the additional valuable quality of being capable of use within an hour or two of laying. Binders formed in accordance with the present invention are suitable for a great variety of uses, e. g. for the production of cable ducts, railway carriage and other floors, roofing material, water-resisting grouting material for tunnels, tubes, blocks, pillars, etc. in lieu of cement. They are also suitable for producing moulded articles in which case they are preferably admixed with a suitable fine powder such as chalk or barium sulphate. As the proportion of bituminous material in a binder is reduced the quantity of aggregate which can be satisfactorily admixed naturally becomes reduced but haveformed satisfactory moulding material with only about 20 per cent. of bituminous material admixed with about per cent. ofchalk.

In order to produce, a hot bituminousspray which sets rapidly to give a hard water-resisting surface and which is then ready immediately for the passage of traffic I mix chalk, alum, coal tar and hard pitch. According to one example I melt together 7 lbs. of gas tar and 1 lb. of hard pitch and thoroughly incorporate 16 lbs. of powderedchalk therewith. One ounce of powderedalum is then added and the mixture thoroughly mixed The resulting mixture is ready for spraying .without further treatment or may be allowed to cool, without injury, being reheated when required for use. dered chalk may be replaced partly or wholly by limestone but chalk is preferred. A suitable tar for this example is obtainable from the South Metropolitan Gas Company Hot bituminous spray prepared as just described is,when cold, tough, resilient and adhesive tothe usual surfaces to which it is applied. It does not appear to cling to the wheels of vehicular traffic even whenit is still warm; Thus I find it can be used immediately after completion of the spraying operation yet' the added material such as stone chips adhere firmly to the sprayed material. If tar isnot readily obtainable, it can be replaced by a suitable oil bitumen although such usually gives inferior results.

A larger proportion of bituminous ma I claim:

1. A bituminous compound for use when heated as a binding or spraying material or cement for admixture with anfaggregate consisting of chalk, coal tar, alum and hard pitch, the proportion of chalk to coaltar being about two parts to one by weight and The powof alum about 1 per cent by weightof the mixture.

2. A spraying or binding material as described in claim 1, wherein the ingredients enter in the following approximate proportions: chalk 50 to 7 5 per cent by weight;

alum 1 per cent by weight; hard pitch 12 i 1 lb. of hard pitch, 16' lbs. of powdered chalk and 1 ounce of powdered alum.

In testimony whereof I have signed my name to this specification.

THOMAS FRASER KING. 

